Multi-Functional Compositions Comprising Concentrated Acids for Enhanced Oil and Gas Recovery

ABSTRACT

The subject invention provides multi-functional biochemical compositions, as well as their use in enhancing oil recovery by, for example, enhancing traditional acid treatments. Advantageously, the compositions and methods of the subject invention are operationally-friendly, cost-effective, and environmentally-friendly approaches to enhancing oil recovery. More specifically, in preferred embodiments, the subject invention provides a multi-functional composition for enhanced oil recovery (EOR) comprising one or more concentrated acids that work in synergy with a combination of one or more surfactants, one or more chelating agents, and one or more solvents to stimulate the flow of oil from a formation.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 17/623,075, filed Dec. 27, 2021; which is aNational Stage Application of International Application No.PCT/US2020/039486, filed Jun. 25, 2020; which claims priority to U.S.Provisional Patent Application No. 62/866,884, filed Jun. 26, 2019, allof which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The safe and efficient production of oil and gas depends on the properfunctioning of hydrocarbon-producing facilities. One of the most commonissues leading to structural failure and production inefficiency withinthese facilities is the accumulation of deposits in the formation and inand around the wellbore, tubing, flow lines, storage tanks, separators,and other components of oil and gas production infrastructure.

These problematic deposits can be formed by, for example, deposits ofprecipitated mineral salts, which can arise as a result of, for example,changes in the pressure, composition and/or temperature of the crudeoil. Scales can result from precipitates of, for example, bariumsulfate, calcium carbonate, strontium sulfate, calcium sulfate, sodiumchloride, silicon dioxide, iron sulfide, iron oxides, iron carbonate,silicates, phosphates and oxides, or any of a number of compounds thatare insoluble or mildly soluble in water.

Systematic inhibition or removal of deposits is crucial to maintainingproperly functioning oil and gas producing facilities. Once even a thinlayer of scale deposits on a surface, such as in a formation porethroat, the rate of further accumulation drastically increases.Furthermore, as an oil well ages, deposits become more prevalent due tochanges in the environment within the formation and the well. Forexample, as reservoir pressure drops, oil production decreases, which inturn decreases flow rates. The slowing of flow rates can lead to thebuildup of organic deposits in the pores of the formation, thus reducinghydrocarbon movement into the wellbore. This can lead to changes intemperature gradients and thus even greater precipitation of deposits,including scale. Thus, the effects are interrelated, cyclical andcompounding, unless they are dealt with consistently.

As the thickness of deposits increases in structures over time, theresult is a gradual decrease in production. In tubing and casingstructures, the deposits begin to reduce the inner diameter of pipingand restrict the free flow of oil and gas. As this occurs, the interiorroughness of the structures also increases, which raises the pumppressure required to move the petroleum product. If left untreated,deposits can ultimately lead to complete blockage. Furthermore,depending upon the location of the precipitation, maintenance and/oremergency repairs can become extremely expensive.

Current methods of deposit removal fall within four main categories:mechanical, chemical, microbial, and thermal removal. Mechanical removaltypically involves the use of scrapers or cutters to physically removedeposits. In tanks where precipitation has occurred, the sides of thetank must often be cut out and manual force applied using, e.g., asledgehammer, to remove the deposits. For pipelines, a process calledmilling can be used, where coiled tubing is run inside tubulars and avariety of chipping bits break away at the deposits. Another processcalled jetting utilizes water and/or chemical washes. Water jetting canbe effective on soft scale, such as halite, but is less effective onsome forms of medium to hard scales, such as calcite and barite. The useof abrasives greatly improves cutting through scale, but can damage thesteel tubulars and valves. In some instances, complete replacement ofpipes is required if deposits become too thick for manual or mechanicalremoval.

Chemical removal can also be implemented, and often involves the use ofacids, solvents or surfactants that can solubilize scale deposits, rustand other debris, or interfere with the crystallization and formation ofthe deposit particles. Hydrochloric acid, acrylic acid, maleic acid,polymers and phosphonates have been used extensively for scaletreatment.

One type of acid treatment, in particular, is known as acidizing, whichinvolves pumping acid into a wellbore or formation to improve the well'sproductivity. The acid restores the permeability of the formation bydissolving the sediments and mud solids that plug the rock pores, thusenlarging the pores and stimulating the flow of hydrocarbons. The acidcan also dissolve formation rock itself to increase permeability.

Another type of acid treatment is known as acid washing, wherein acid isused to dissolve sediments in the tubulars and wellbores of an oil well,rather than the formation. This can be useful for fixing and/orpreventing damage to perforations, tubing, and the near-wellbore zonecaused by fine particles, mud or cement filtrate, scale and debris fromwell operations. While acid treatments can be effective chemicalmechanisms for removing and/or inhibiting scale and other deposits inoil wells and formations, acids such as hydrochloric acid, can becostly, particularly in high-heat environments. Hydrochloric acid isespecially reactive under these conditions and can cause corrosion ofmetal equipment, such as the well casing. Organic acids can be usedinstead due to their slower reaction rates and lower corrosionpotential, but they are not suitable for all formation types.

Accumulation of deposits in oil and on oil processing equipment can havea compounding effect. Unless these compounds are removed, operators canbe faced with lowering oil recovery rates, improper function of pumps,blocked tubing and pipes, and potential for total loss of production.Cost, safety in processing, large-scale sustainability, and damage toformations must be accounted for when developing methods for removingthese deposits to ensure long-term efficiency of hydrocarbon production.

Because of the importance of safe and efficient oil and gas productionand the difficulties caused by scale deposits in production andtransport of oil and gas, there is a continuing need for improvedmethods of inhibiting, and/or removing such deposits from,hydrocarbon-producing facilities.

BRIEF SUMMARY OF THE INVENTION

The subject invention provides multi-functional biochemicalcompositions, as well as their use in enhancing acid treatments in oilwells, wellbores and reservoirs. Advantageously, the compositions andmethods of the subject invention provide operationally-friendly,cost-effective, and environmentally-friendly approaches to enhancing oilrecovery from an oil-bearing subterranean formation.

More specifically, in preferred embodiments, the subject inventionprovides a multi-functional composition for enhanced oil recovery (EOR)comprising one or more concentrated acids, one or more surfactants, oneor more chelating agents, and one or more solvents. Optionally, one ormore co-surfactants are included in the composition in order to enhanceits beneficial effects in an oil-bearing formation.

Advantageously, in preferred embodiments, the composition can utilizeenvironmentally-friendly, biodegradable ingredients that work togetherto stimulate the flow of oil from an oil well. In addition to EOR, thecomposition is also useful for one or more of the following: dissolvingand dispersing scale deposits that have plugged rock pore throats in aformation; removing scale that has deposited onto equipment associatedwith oil production and processing; sequestering heavy metals present incrude oil fluids; preventing and/or reducing formation of asphalteneagglomerates and/or deposits in oil and on surfaces of equipmentassociated with a formation; dispersing paraffin deposits; increasingthe mobility of crude oil during recovery from a well; and increasingthe wettability of formation rock.

In preferred embodiments, the concentrated acid(s) of the subjectcomposition are selected from one or more of hydrochloric acid (HCl),hydrofluoric acid (HF), and/or an organic acid, such as, for example,acetic acid or formic acid. In some embodiments, the type and/orcombination of acid types is dependent upon the composition of thesubterranean formation, and/or the composition of the scale or otherdeposits in the well and/or formation.

In certain embodiments, the amount of concentrated acid in thecomposition is about 1% to about 20% v/v. Preferably, the concentratedacid has a purity of about 80% or greater.

In preferred embodiments, the surfactants of the subject compositioncomprise biosurfactants or a blend of more than one type ofbiosurfactant. Biosurfactants useful according to the subject inventioninclude, for example, glycolipids, cellobiose lipids, lipopeptides,fatty acid esters, fatty acid ethers, flavolipids, phospholipids, andhigh-molecular-weight polymers/biopolymers such as lipoproteins,lipopolysaccharide-protein complexes, and/orpolysaccharide-protein-fatty acid complexes. Preferably, thebiosurfactants are produced by microorganisms.

In one embodiment, the biosurfactants are one or more glycolipids suchas, for example, rhamnolipids (RLP), rhamnose-d-phospholipids, trehaloselipids, trehalose dimycolates, trehalose monomycolates,mannosylerythritol lipids (MEL), cellobiose lipids, ustilagic acidsand/or sophorolipids (SLP) (including lactonic forms and/or acidicforms). In one embodiment, the biosurfactants are one or morelipopeptides, such as, for example, surfactin, iturin, fengycin,arthrofactin, viscosin, amphisin, syringomycin, and/or lichenysin. Inone embodiment, the biosurfactants are one or more fatty acid estersand/or one or more fatty acid ethers. In one embodiment, thebiosurfactants are one or more other types of biosurfactants, such as,for example, cardiolipin, emulsan, lipomanan, alasan, and/or liposan.

In one embodiment, the surfactants can be one or more microbialcompounds having physical properties and/or behaviors similar to thoseof biosurfactants, but which are not commonly known as biosurfactants.These compounds can be fatty acid esters and/or fatty acid ethers. Incertain embodiments, the fatty acid compounds can comprise carbon chainswith 6 to 22 carbon atoms. In certain embodiments, the fatty acid(s) ofthe fatty acid compounds are unsaturated.

In certain embodiments, the total surfactant concentration included inthe subject composition is less than 5,000 ppm. In certain embodiments,the total surfactant concentration is about 0.01% to about 10%, or about0.05% to about 5%.

In preferred embodiments, the surfactant concentration is no lower thancritical micelle concentration (CMC) at the time the composition isintroduced into the formation (e.g., after natural dilution occurswithin the formation). Such concentration can be calculated by theskilled artisan having the benefit of the subject disclosure.

In one embodiment, the surfactants of the compositions are obtainedthrough cultivation of microorganisms using processes ranging from smallto large scale. The cultivation process can be, for example, submergedcultivation, solid state fermentation (SSF), and/or a combinationthereof.

In certain embodiments, the surfactants can be added to the compositionin purified form and/or in crude form. In one embodiment, thesurfactants can be added to the composition in the form of a microbialfermentation product, containing liquid fermentation broth (supernatant)and, optionally, microbial cells resulting from submerged cultivation ofa surfactant-producing microbe. The microbes can be bacteria, yeastsand/or fungi. Preferably, the microbial cells are inactivated prior tobeing added to the composition.

Advantageously, the surfactants can serve as adjuvants, helping toreduce the total amount of the multifunctional EOR composition requiredfor treatment and helping reduce the time required to achieve thedesired results. The surfactants, as adjuvants, increase the penetrationof the other active components into the formation and into clogging andcontaminating deposits, such as scale. The surfactants can also serve tocounteract the potentially corrosive effects of the concentrated acidon, for example, metal equipment, by acting as corrosion inhibitors. Thesurfactants can also serve as active components for achieving EOR andother beneficial functions in an oil-bearing formation, due to, forexample, their surface and interfacial tension reduction properties.

In one embodiment, the chelating agents of the subject compositioncomprise, for example, EDTA, citric acid, sodium citrate, sodiumacetate, or any mixture thereof. In one embodiment, the chelating agentscan be added to the composition in amounts of about 5 g/L or more. In aspecific embodiment, the chelating agents comprise a mixture of EDTA,sodium citrate, and citric acid.

Advantageously, the chelating agents can help dissolve and/or inhibitscale deposits, can help remove and/or sequester heavy metals, such asnickel and vanadium, from oil, and can reduce asphaltene buildup byforming complexes with heavy metal molecules that can serve as anchorsfor asphaltene particle agglomeration. Additionally, in someembodiments, the chelating agents can serve as co-surfactants, thusfurther enhancing the efficiency and potency of the effects of thecomposition. This is particularly true with the use of EDTA, which canserve as an anionic co-surfactant in some embodiments.

In one embodiment, the solvents of the subject composition are selectedfrom alcohols, ionic and/or semi-ionic liquids, and ammonium hydroxide.

Alcohols according to the subject composition can include, for example,ethanol, butanol, propanol, and/or isopropyl alcohol. In a specificembodiment, the alcohol is isopropyl alcohol at a concentration of about2 ml/L to 100 ml/L.

Ionic and/or semi-ionic liquids according to the subject composition caninclude, for example, ethyl ammonium nitrate or glycerin/magnesiumsulfate heptahydrate. Advantageously, ionic and/or semi-ionic liquidscan be useful in, for example, dissolving asphaltene agglomeratespresent in crude oil fluids and on equipment. Preferably, theconcentration of ionic or semi-ionic liquid is about 0.1% to about 5%.

In some embodiments, the composition comprises ammonium hydroxide as asolvent and/or as a pH adjuster. Preferably, the ammonium hydroxide ispresent in the composition at a concentration of about 1 ml/L to 50ml/L.

The subject composition can further comprise other compounds and/oradditives, such as, for example, carriers (e.g., water, brine fluids),ammonium salts (e.g., monoammonium phosphate) and/or enzymes (e.g.,derived from Aspergillus spp.). These additional compounds can be addedin amounts ranging from, for example, 0.001% to 80% or greater, byweight or volume.

In one exemplary embodiment, the composition comprises concentratedhydrochloric acid; one or more surfactants; ammonium hydroxide;isopropyl alcohol; a mixture of EDTA, sodium citrate and citric acid;and, optionally, monoammonium phosphate. The components can be mixedtogether in water or brine fluids.

In one embodiment, the subject invention provides methods for improvingoil production. In specific embodiments, the methods provide forenhanced acid washing and/or acidizing treatments, wherein one or moreconcentrated acids, as well as one or more surfactants, one or morechelating agents, and one or more solvents, are applied into a formationand/or an oil well and/or wellbore associated therewith. Optionally, oneor more co-surfactants are also applied.

In one embodiment, the methods comprise applying a multipurpose EORcomposition of the subject invention to the formation, well and/orwellbore. Advantageously, the methods can be used to enhance oilrecovery from a well that has experienced a decline in oil productionrates, including depleted stripper (marginal) wells.

Application of the multipurpose EOR composition can be performed duringdrilling operations (e.g., while drilling, while tripping-in ortripping-out of the hole, while circulating mud, while casing, whileplacing a production liner, and/or while cementing, etc.). Applicationcan also occur as a production treatment, for example, by introducingthe composition into an oil well after oil production is underway and/orafter a decline in the rate of oil production from the formation hasoccurred.

In some embodiments, the composition can be introduced into theformation through perforations in the casing. The composition may beforced into the surrounding formation by applied pressure or, if thecomposition is allowed to set at the bottom of the casing, thecomposition may seep into the formation without additional pressure. Thecomposition permeates the formation, improving the rate of oil recoveryby, for example, dissolving blockages in the formation pore throats.

Advantageously, the methods are useful for a variety of functions inaddition to EOR, including improving the quality of crude fluids, andmaintenance of oil production and processing equipment. In someembodiments, these functions are interrelated.

In some embodiments, the methods result in EOR through, for example,stimulation of the flow of oil from an oil well; prevention and/orreduction of asphaltene agglomeration in oil and/or deposition onequipment surfaces; dispersal of paraffin deposits; increase in themobility of crude oil during recovery; and increase in the wettabilityof formation rock.

Furthermore, in some embodiments, the concentrated acid(s) work insynergy with the one or more surfactants, one or more chelating agents,one or more solvents, and/or one or more optional co-surfactants, todissolve and/or disperse mineral scale deposits that have deposited in,for example, tubulars or the wellbore, and/or that have pluggedformation rock pore throats. In certain embodiments, this synergyprovides for enhanced acid treatments, meaning the treatment is moreeffective for stimulating the flow of oil from a formation than usingconcentrated acids alone.

In one embodiment, improved crude oil quality is achieved through thesequestration and/or removal of heavy metals, such as nickel and/orvanadium, present in crude oil; reduction and/or prevention ofasphaltene agglomerates in the oil; and modulation of the pH of the oil.

In certain embodiments, the methods are also useful for maintenance ofequipment, for example, pipes, tubulars, drills, pumps, casings, tanks,rods, boreholes, and other structures and equipment involved in oiland/or gas production and processing. Any equipment or component of oilproduction, processing, transportation, storage and/or refining can betreated and maintained with a composition of the subject invention.

In one embodiment, maintenance of equipment is achieved through theprevention, removal, and/or dispersal of contaminating deposits, such asscale, paraffins and asphaltenes, which form on the equipment. Incertain embodiments, this also serves to prevent under-deposit corrosionof equipment.

Advantageously, in some embodiments, the subject treatments can freeclogged pores, channels and/or tubing, and/or reduce the capillarypressure in a formation, thus allowing for increased oil production fromdepleted wells, and further, even allowing inoperable wells to resumenormal operation. Additionally, through a variety of mechanisms, thesubject treatments can stimulate wells, improve the quality of crudeoil, and help in the maintenance of oil production and processingequipment.

DETAILED DESCRIPTION

The subject invention provides multi-functional biochemicalcompositions, as well as their use in enhancing oil recovery from anoil-bearing formation. In certain embodiments, the subject inventionprovides enhanced acid treatments in oil wells, wellbores andreservoirs. Advantageously, the compositions and methods of the subjectinvention provide operationally-friendly, cost-effective, andenvironmentally-friendly approaches to enhancing oil recovery.

In preferred embodiments, the subject invention provides amulti-functional composition for enhanced oil recovery (EOR) comprisingone or more concentrated acids, one or more surfactants, one or morechelating agents, and one or more solvents. Optionally, one or moreco-surfactants are included in the composition in order to enhance itsbeneficial effects in an oil-bearing formation.

In one embodiment, the subject invention provides efficient methods forimproving oil production. In certain embodiments, the methods are usedfor enhancing acid washing and/or acidizing treatments of oil wells,wellbores, and/or subterranean formations.

In one embodiment, the methods comprise introducing a multipurpose EORcomposition of the subject invention into an oil-bearing subterraneanformation. Advantageously, the methods can be used to enhance oilrecovery from a well that has experienced a decline in oil productionrates, including depleted stripper (marginal) wells.

Selected Definitions

As used herein, “contaminant” refers to any substance that causesanother substance or object to become fouled, clogged and/or impure.Contaminants can be living or non-living and can be inorganic or organicsubstances or deposits. Furthermore, contaminants can include, but arenot limited to, scales, hydrocarbons, such as petroleum, tar orasphaltenes; fats, oils and greases (FOG); lipids; waxes, such asparaffins; resins; heavy metals; biofilms; or any other substancesreferred to as, for example, dirt, dust, sludge, crud, slag, grime,scum, plaque, buildup, or residue. Reference to “scale” means any typeof scale that results from the precipitation of, for example, bariumsulfate, calcium carbonate, calcium sulfate, calcium oxalate, magnesiumhydroxide, magnesium oxide, silicates, strontium sulfate, aluminum oxidehydroxides, aluminosilicates, magnetite or nickel ferrite, sodiumchloride, silicon dioxide, iron sulfide, iron oxides, iron carbonate,copper, phosphates, oxides, and any other mineral compound that canprecipitate and form deposits.

As used herein, a “heavy metal” is a chemical element with a specificgravity at least five times that of water. Examples of heavy metalsinclude, but are not limited to, arsenic, cadmium, chromium, copper,iron, lead, manganese, mercury, nickel, vanadium and zinc. Many heavymetals are present in crude oil fluids, and can corrode equipment aswell as poison the catalysts used in fluid catalytic cracking and oilrefineries. Furthermore, heavy metals can serve as anchors for theagglomeration of, for example, asphaltene particles, which canaccumulate, leading to a reduction in crude oil quality and theformation of deposits on equipment surfaces.

As used herein, “cleaning” as used in the context of contaminants meansremoval or reduction of contaminants from a surface or a piece ofequipment. Cleaning can include treating, purifying, defouling,decontaminating, clearing or unclogging, and can be achieved by anymeans, including but not limited to, melting, dispersing, emulsifying,dissolving, scraping, degrading, blasting, soaking, or cleaving thecontaminant.

As used herein, “prevention” means avoiding, delaying, forestalling,inhibiting or minimizing the onset or progression of an occurrence orsituation. Prevention can include, but does not require, absolute orcomplete prevention, meaning the occurrence or situation may stilldevelop at a later time and/or with a lesser severity than it wouldwithout preventative measures. Prevention can include reducing theseverity of the onset of an occurrence or situation, and/or inhibitingthe progression thereof to one that is more severe. In certainembodiments, the subject invention can be useful for, for example,preventing the crystallization, deposition and/or re-deposition ofscale, paraffins and/or asphaltenes.

As used herein, reference to a “microbe-based composition” means acomposition that comprises components that were produced as the resultof the growth of microorganisms or other cell cultures. Thus, themicrobe-based composition may comprise the microbes themselves and/orby-products of microbial growth. Preferably, the compositions accordingto the subject invention comprise inactivated microbes, or have beenseparated from the microbes altogether. The by-products of microbialgrowth may be, for example, metabolites (e.g., biosurfactants), cellmembrane components, expressed proteins, and/or other cellularcomponents.

The subject invention further provides “microbe-based products,” whichare products that are to be applied in practice to achieve a desiredresult. The microbe-based product can be simply the microbe-basedcomposition harvested from the microbe cultivation process.Alternatively, the microbe-based product may comprise furtheringredients that have been added. These additional ingredients caninclude, for example, stabilizers, buffers, appropriate carriers, suchas water, salt solutions, or any other appropriate carrier, addednutrients to support further microbial growth, non-nutrient growthenhancers, and/or agents that facilitate tracking of the microbes and/orthe composition in the environment to which it is applied. Themicrobe-based product may also comprise mixtures of microbe-basedcompositions. The microbe-based product may also comprise one or morecomponents of a microbe-based composition that have been processed insome way such as, but not limited to, filtering, centrifugation, lysing,drying, purification and the like.

As used herein, an “isolated” or “purified” nucleic acid molecule,polynucleotide, polypeptide, protein or organic compound, such as asmall molecule, is substantially free of other compounds, such ascellular material, with which it is associated in nature. In certainembodiments, purified compounds are at least 60% by weight the compoundof interest. Preferably, the preparation is at least 75%, morepreferably at least 90%, and most preferably at least 99%, by weight thecompound of interest. For example, a purified compound is one that is atleast 90%, 91%, 92%, 93%, 94%, 95%, 98%, 99%, or 100% (w/w) of thedesired compound by weight. Purity is measured by any appropriatestandard method, for example, by column chromatography, thin layerchromatography, or high-performance liquid chromatography (HPLC)analysis.

Ranges provided herein are understood to be shorthand for all of thevalues within the range. For example, a range of 1 to 20 is understoodto include any number, combination of numbers, or sub-range from thegroup consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19 and 20, as well as all intervening decimal values between theaforementioned integers such as, for example, 1.1, 1.2, 1.3, 1.4, 1.5,1.6, 1.7, 1.8, and 1.9. With respect to sub-ranges, “nested sub-ranges”that extend from either end point of the range are specificallycontemplated. For example, a nested sub-range of an exemplary range of 1to 50 may comprise 1 to 10, 1 to 20, 1 to 30, and 1 to 40 in onedirection, or 50 to 40, 50 to 30, 50 to 20, and 50 to 10 in the otherdirection.

As used herein, “reduces” means a negative alteration of at least 1%,5%, 10%, 25%, 50%, 75%, or 100%.

As used herein, “reference” means a standard or control condition. A“metabolite” refers to any substance produced by metabolism (e.g., agrowth by-product) or a substance necessary for taking part in aparticular metabolic process. A metabolite can be an organic compoundthat is a starting material, an intermediate in, or an end product ofmetabolism. Examples of metabolites include, but are not limited to,biosurfactants, enzymes, acids, solvents, gasses, alcohols, proteins,vitamins, minerals, microelements, amino acids, and polymers.

As used herein, “surfactant” means a compound that lowers the surfacetension (or interfacial tension) between two liquids, between a liquidand a gas, or between a liquid and a solid. Surfactants act as, e.g.,detergents, wetting agents, emulsifiers, foaming agents, and/ordispersants. A “biosurfactant” is a surface-active substance produced bya living cell. The transitional term “comprising,” which is synonymouswith “including,” or “containing,” is inclusive or open-ended and doesnot exclude additional, unrecited elements or method steps. By contrast,the transitional phrase “consisting of” excludes any element, step, oringredient not specified in the claim. The transitional phrase“consisting essentially of” limits the scope of a claim to the specifiedmaterials or steps “and those that do not materially affect the basicand novel characteristic(s)” of the claimed invention. Use of the term“comprising” contemplates other embodiments that “consist” or “consistessentially of” the recited component(s).

Unless specifically stated or obvious from context, as used herein, theterm “or” is understood to be inclusive. Unless specifically stated orobvious from context, as used herein, the terms “a,” “and” and “the” areunderstood to be singular or plural.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. About can beunderstood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromcontext, all numerical values provided herein are modified by the termabout.

The recitation of a listing of chemical groups in any definition of avariable herein includes definitions of that variable as any singlegroup or combination of listed groups. The recitation of an embodimentfor a variable or aspect herein includes that embodiment as any singleembodiment or in combination with any other embodiments or portionsthereof.

All references cited herein are hereby incorporated by reference intheir entirety.

Compositions

In preferred embodiments, the subject invention providesmulti-functional compositions for enhanced oil recovery (EOR). Morespecifically, in preferred embodiments, the subject invention provides amulti-functional EOR composition comprising one or more concentratedacids, one or more surfactants, one or more chelating agents, and one ormore solvents. Optionally, one or more co-surfactants are included inthe composition in order to enhance its beneficial effects in anoil-bearing formation.

Advantageously, in preferred embodiments, the composition can compriseenvironmentally-friendly, biodegradable ingredients that work togetherto stimulate the flow of oil from an oil well. Furthermore, thecomposition can be useful for enhancing acid treatments, such asacidizing and/or acid washing, in formations, oil wells, wellbore,and/or other associated equipment.

In addition to EOR, the composition is also useful for one or more ofthe following: dissolving and dispersing scale deposits that haveplugged rock pore throats in a formation; removing scale that hasdeposited onto equipment associated with oil production and processing;sequestering heavy metals present in crude oil fluids; preventing and/orreducing formation of asphaltene agglomerates and/or deposits in oil andon surfaces of equipment associated with a formation; dispersingparaffin deposits; increasing the mobility of crude oil during recoveryfrom a well; and increasing the wettability of formation rock.

In preferred embodiments, the concentrated acid(s) of the subjectcomposition comprise one or more of hydrochloric acid (HCl),hydrofluoric acid (HF), and/or an organic acid, such as, for example,acetic acid or formic acid. Preferably, the concentrated acid and/oracids are concentrated to a purity of at least 80%, at least 90%, atleast 95%, or at least 98%.

In some embodiments, the type and/or combination of acid types isdependent upon the geologic composition of the subterranean formation,and/or the composition of the scale or other deposits in the well and/orformation. For example, in some embodiments, HCl is used when theformation comprises carbonate reservoirs, or limestones and dolomites.HF can be useful for dissolving quartz, sand and clay from reservoirrocks. In some embodiments, a combination of acids is used because, forexample, the formation is heterogeneous in its geologic composition.

In certain embodiments, the amount of concentrated acid in thecomposition is about 1% to about 20% v/v, about 5% to about 15%, orabout 7.5% to about 10%.

In preferred embodiments, the surfactants of the subject compositioncomprise microbial-produced compounds having surface and interfacialtension reducing properties. Advantageously, the surfactants can serveas adjuvants by increasing the penetration of the other activecomponents into the formation and into clogging and contaminatingdeposits, such as scale. This helps to reduce the total amount of themultifunctional EOR composition required for treatment and helps reducethe time required to achieve the desired results.

The surfactants can also serve to counteract the potentially corrosiveeffects of the concentrated acid on, for example, metal equipment, byacting as corrosion inhibitors. Furthermore, the surfactants can alsoserve as active components for achieving EOR and other beneficialfunctions in an oil-bearing formation, due to, for example, theirsurface and interfacial tension reduction properties.

In certain embodiments, the surfactants are microbial biosurfactants ora blend of more than one type of biosurfactant. Biosurfactants are astructurally diverse group of surface-active substances produced bymicroorganisms. Biosurfactants are biodegradable and can produced usingselected organisms in or on renewable substrates. All biosurfactants areamphiphiles consisting of two parts: a polar (hydrophilic) moiety andnon-polar (hydrophobic) group. Due to their amphiphilic structure,biosurfactants increase the surface area of hydrophobic water-insolublesubstances, increase the water bioavailability of such substances, andchange the properties of bacterial cell surfaces. Furthermore,biosurfactants accumulate at interfaces, and reduce the surface andinterfacial tension between the molecules of liquids, solids, and gases,thus leading to the formation of aggregated micellar structures insolution.

Biosurfactants according to the subject invention include, for example,glycolipids, cellobiose lipids, lipopeptides, fatty acid estercompounds, fatty acid ether compounds, flavolipids, phospholipids, andhigh-molecular-weight polymers/biopolymers such as lipoproteins,lipopolysaccharide-protein complexes, and/orpolysaccharide-protein-fatty acid complexes. Preferably, thebiosurfactants are produced by microorganisms

In one embodiment, the biosurfactants can be one or more glycolipidssuch as, for example, rhamnolipids, rhamnose-d-phospholipids, trehaloselipids, trehalose dimycolates, trehalose monomycolates,mannosylerythritol lipids, cellobiose lipids, ustilagic acid and/orsophorolipids.

In an exemplary embodiment, the surfactant is a sophorolipid (SLP). TheSLP can be an esterified SLP, a lactonic form SLP, and/or an acidic formSLP. Further included are mono-acetylated SLP, di-acetylated SLP, SLPwith varying hydrophobic chain lengths, SLP with fatty acid-amino acidcomplexes attached, and others as are described within in thisdisclosure. In some embodiments, a mixture of SLP types is utilized.

In preferred embodiments, the SLP molecules according to the subjectinvention are represented by General Formula (1) and/or General Formula(2), and are obtained as a collection of 30 or more types of structuralhomologues having different fatty acid chain lengths (R³), and, in someinstances, having an acetylation or protonation at R¹ and/or R².

In General Formula (1) or (2), R⁰ can be either a hydrogen atom or amethyl group. R¹ and R² are each independently a hydrogen atom or anacetyl group. R³ is a saturated aliphatic hydrocarbon chain, or anunsaturated aliphatic hydrocarbon chain having at least one double bond,and may have one or more Substituents.

Examples of the Substituents include halogen atoms, hydroxyl, lower(C1-6) alkyl groups, halo lower (C1-6) alkyl groups, hydroxy lower(C1-6) alkyl groups, halo lower (C1-6) alkoxy groups, and the like. R3typically has 11 to 20 carbon atoms, preferably 13 to 17 carbon atoms,and more preferably 14 to 16 carbon atoms. Examples of the halogen atomsor halogen atoms bound to alkyl groups or alkoxy groups includefluorine, chlorine, bromine, and iodine.

In an exemplary embodiment, the surfactant is a mannosylerythritol lipid(MEL), comprising either 4-O-B-D-mannopyranosyl-meso-erythritol or1-O-B-D-mannopyranosyl-meso-erythritol as the hydrophilic moiety, andfatty acid groups and/or acetyl groups as the hydrophobic moiety. One ortwo of the hydroxyls, typically at the C4 and/or C6 of the mannoseresidue, can be acetylated. Furthermore, there can be one to threeesterified fatty acids, from 8 to 12 carbons or more in chain length.

MEL molecules can be modified, either synthetically or in nature. Forexample, MEL can comprise different carbon-length chains or differentnumbers of acetyl and/or fatty acid groups.

MEL molecules and/or modified forms thereof according to the subjectinvention can include, for example, tri-acylated, di-acylated,mono-acylated, tri-acetylated, di-acetylated, mono-acetylated andnon-acetylated MEL, as well as stereoisomers and/or constitutionalisomers thereof.

In certain specific embodiments, the MEL molecules are selected frommembers of the following groups: MEL A (di-acetylated), MEL B(mono-acetylated at C4), MEL C (mono-acetylated at C6), MEL D(non-acetylated), tri-acetylated MEL A, tri-acetylated MEL B/C, andfurther including all possible isomers of the members of these groups.

Other MEL-like molecules that exhibit similar structures and similarproperties, can also be produced according to the subject invention,e.g., mannosyl-mannitol lipids (MML), mannosyl-arabitol lipids (MAL),and/or mannosyl-ribitol lipids (MRL).

In one embodiment, the biosurfactants can be one or more lipopeptides,such as, for example, surfactin, iturin, fengycin, arthrofactin,viscosin, amphisin, syringomycin, and/or lichenysin.

In one embodiment, the biosurfactants can be one or more other types ofbiosurfactants, such as, for example, cardiolipin, emulsan, lipomanan,alasan, and/or liposan.

In one embodiment, the surfactants can comprise one or moremicrobial-produced fatty acid ester compounds having physical propertiesand/or behaviors similar to those of biosurfactants, but which are notcommonly known as biosurfactants.

In certain embodiments, the fatty acid ester compounds can berepresented by the following formula:

wherein

-   -   Z═O    -   R₁=C₆ to C₂₂ saturated or unsaturated hydrocarbon, or an        epoxide, or cyclopropane thereof    -   Y₁=H, C₁-C₅ hydrocarbon, or hydroxyl at any position along R₁    -   Y₂=H, C₁-C₅ hydrocarbon, or hydroxyl at any position along R₁    -   R₂=C₁-C₁₀ saturated or unsaturated, branched or unbranched,        hydrocarbon.

In certain embodiments, the fatty acid ester compounds can include, forexample, highly esterified oleic fatty acids, such as oleic fatty acidethyl esters and/or oleic fatty acid methyl esters (FAME).

In one embodiment, the surfactants can comprise one or moremicrobial-produced fatty acid ether compounds having physical propertiesand/or behaviors similar to those of biosurfactants, but which are notcommonly known as biosurfactants.

In certain embodiments, the fatty acid ether compounds can berepresented by the following formula:

wherein

-   -   R₁=C₆ to C₂₂ saturated or unsaturated hydrocarbon, or an        epoxide, or cyclopropane thereof    -   Y₁=H, C₁-C₅ hydrocarbon, or hydroxyl at any position along R₁    -   Y₂=H, C₁-C₅ hydrocarbon, or hydroxyl at any position along R₁    -   R₂=C₁-C₁₀ saturated or unsaturated, branched or unbranched,        hydrocarbon.

In certain embodiments, the fatty acid ether comprises a vinyl ether ora divinyl ether.

The surfactants can be used at relatively low concentrations. In certainembodiments, the total surfactant concentration included in the subjectcomposition is 5,000 ppm or less, 4,000 ppm or less, or 3,000 ppm orless. In a specific embodiment, the total surfactant concentration isabout 2,500 ppm.

In certain embodiments, the total surfactant concentration is about0.01% to about 10% v/v, about 0.05% to about 5%, about 0.1% to about 1%,or about 0.5% to about 0.75%. In preferred embodiments, the surfactantconcentration is no lower than critical micelle concentration (CMC) atthe time the composition is introduced into the formation (e.g., afternatural dilution occurs within the formation). Such concentration can becalculated by the skilled artisan having the benefit of the subjectdisclosure.

In one embodiment, the surfactants of the compositions are obtainedthrough cultivation of microorganisms using processes ranging from smallto large scale. The cultivation process can be, for example, submergedcultivation, solid state fermentation (SSF), and/or a combinationthereof.

In one embodiment, the subject invention provides methods of producing amicrobial metabolite by cultivating a microbe strain of the subjectinvention under conditions appropriate for growth and metaboliteproduction; and, optionally, purifying the metabolite. In specificembodiments, the metabolite is a surfactant growth by-product,preferably, a biosurfactant or an esterified oleic fatty acid.

The microbial growth by-product produced by the microorganisms ofinterest may be retained in the microorganisms or secreted into theliquid medium. Thus, in one embodiment, a microbe-based product of thesubject invention comprises simply the fermentation broth containingmicrobial metabolites produced by a microorganism and/or any residualnutrients. The product of fermentation may be used directly withoutextraction or purification. In another embodiment, the method forproducing microbial growth by-product may further comprise steps ofconcentrating and purifying the microbial growth by-product of interest.Thus, the composition may comprise microbial metabolites, e.g.,microbial surfactants, in purified form.

In certain embodiments, the surfactants can be added to themultifunctional EOR composition in purified form and/or in crude form.In one embodiment, the surfactants can be added to the composition inthe form of a microbial fermentation product, containing liquidfermentation broth (supernatant) and, optionally, microbial cellsresulting from submerged cultivation of a surfactant-producing microbe.The microbes can be bacteria, yeasts and/or fungi. Preferably, themicrobial cells are inactivated prior to being added to the composition.

In certain embodiments the microorganisms can be, for example,Arthrobacter spp.; Bacillus spp. (B. subtilis, B. pumillus, B.licheniformis, B. amyloliquefaciens, B. megaterium, B. cereus);Campylobacter spp.; Candida spp. (e.g., C. albicans, C. rugosa, C.tropicalis, C. lipolytica, C. torulopsis); Cornybacterium spp.;Flavobacterium spp.; Pichia spp. (e.g., P. anomala, P. guilliermondii,P. occidentalis); Pseudomonas spp. (e.g., P. aeruginosa, P.chlororaphis, P. putida, P. florescens, P. fragi, P. syringae);Pseudozyma spp. (e.g., P. aphidis); Rhodococcus spp. (e.g., R.erythropolis); Starmerella spp. (e.g., S. bombicola, S. apicola);Ustilago spp. (e.g., U. maydis); Wickerhamomyces spp. (e.g., W.anomalus), and others as are described elsewhere in the presentdescription.

In preferred embodiments, the multi-functional EOR composition furthercomprises one or more chelating agents or chelators. As used herein,“chelating agents,” or “chelators” are active complex ion-forming agentscapable of removing a metal ion from a system by forming a complex sothat the metal ion, for example, cannot readily participate in orcatalyze oxygen radical formation.

Examples of chelating agents suitable for the present invention include,but are not limited to, dimercaptosuccinic acid (DMSA),2,3-dimercaptopropanesulfonic acid (DMPS), alpha lipoic acid (ALA),thiamine tetrahydrofurfuryl disulfide (TTFD), penicillamine,ethylenediaminetetraacetic acid (EDTA), sodium acetate, sodium citrateand citric acid. In one embodiment, a mixture of chelators is used.

In a specific embodiment, the chelating agents comprise a mixture ofEDTA, sodium citrate, and citric acid. The total concentration ofchelating agents can be, for example, about 1 g/L to about 20 g/L ormore, about 2.5 g/L to about 15 g/L, or about 5 g/L to about 10 g/L.

Advantageously, the chelating agents can help dissolve and/or inhibitscale, paraffin and/or asphaltene deposits, can help remove and/orsequester heavy metals, such as nickel and vanadium, from oil, and canreduce asphaltene buildup by forming complexes with heavy metalmolecules that can serve as anchors for asphaltene particleagglomeration.

Additionally, in some embodiments, the chelating agents can serve asco-surfactants, further enhancing the efficiency and potency of theeffects of the composition. For example, chelating agents, such as EDTA,can take on a negative charge, thus enhancing descaling by sequesteringpositively charged ions, such as calcium ions, as well as inhibitingfuture scale deposition. In a specific embodiment, the EDTA serves as aparticularly effective anionic co-surfactant.

In preferred embodiments, the multi-functional EOR composition furthercomprises one or more solvents selected from alcohols, ionic and/orsemi-ionic liquids, and ammonium hydroxide.

Alcohols according to the subject composition can include, for example,ethanol, butanol, propanol, and/or isopropyl alcohol. In a specificembodiment, the alcohol is isopropyl alcohol at a concentration of about1 ml/L to about 100 ml/L, about 2 ml/L to about 50 ml/L, or about 4 ml/Lto about 25 ml/L of the compositions.

In some embodiments, the composition further comprises an ionic liquidas a solvent. Ionic liquids can act as co-solvents and can prevent theformation of ring bonds in hydrocarbon compositions, which is one causeof hydrocarbon precipitation. Ionic liquids can also prevent and/orreduce the formation and deposition of asphaltene particles.

Ionic liquids are composed entirely of ions, which can include cations,anions and/or a combination thereof. Many ionic liquids are in the formof organic salts with melting points below 100 ° C., or often even lowerthan room temperature. The most common ionic liquids are those preparedfrom organic-based cations and inorganic or organic anions. At least oneion has a delocalized charge and one component is organic, whichprevents the formation of a stable crystal lattice. Ionic liquids may besuitable, for example, for use as catalysts and solvents in alkylationand polymerization reactions, as well as in dimerization,oligomerization acetylation, metatheses and copolymerization reactions.Properties of ionic liquids, such as melting point, viscosity andsolubility are determined by the substituents on the organic componentand by the counter-ion.

Exemplary ionic liquids suitable for the subject composition include,but are not limited to, ethyl ammonium nitrate or glycerin/magnesiumsulfate heptahydrate. Preferably, the concentration of ionic liquid inthe composition is about 0.01% to about 10%, or about 0.1% to about 5%.

In some embodiments, the composition can further comprise ammoniumhydroxide (e.g., a 70% solution) as a solvent. Preferably, ammoniumhydroxide is present in the composition at a concentration of about 1ml/L to 50 ml/L, about 2 ml/L to about 25 ml/L, or about 3 ml/L to about10 ml/L.

Advantageously, ammonium hydroxide can also serve as a pH adjuster. Theammonium hydroxide balances the pH of the composition towards, or at, aneutral pH (e.g., about pH 6 to 8). This can be useful for improving theacid number of crude oil recovered from the treated formation, as wellas for preventing the corrosion of equipment due to contact with theconcentrated acids.

In some embodiments, the composition further comprises salts and/ormineral salts selected from phosphorous, magnesium, potassium, glucoseand ammonium. For example, ammonium phosphate, monoammonium phosphate,diammonium phosphate, ammonium chloride, or another dibasic or monobasicsalt can be included at a concentration of about 1 g/L to about 20 g/L,or about 2 g/L to about 10 g/L. In a specific embodiment, the salt ismonoammonium phosphate.

In one exemplary embodiment, the composition comprises water and/orbrine and: concentrated hydrochloric acid; one or more surfactants;ammonium hydroxide; isopropyl alcohol; a mixture of EDTA, sodium citrateand citric acid; and, optionally, monoammonium phosphate. In a specificembodiment, the one or more surfactants comprise MEL and/or SLP. Inanother embodiment, the one or more surfactants comprise esterifiedoleic fatty acids.

The subject composition can comprise further additives. The additivescan be, for example, carriers, buffers, other microbe-based compositionsproduced at the same or different facility, viscosity modifiers,preservatives, tracking agents, biocides, enzymes, surfactants,emulsifying agents, lubricants, solubility controlling agents, pHadjusting agents, stabilizers, ultra-violet light resistant agents,and/or other ingredients specific for an intended use.

The further additives can be added in amounts ranging from, for example,0.001% to 80% or greater, by weight or volume, as needed, or up to about50% by weight or more.

In one embodiment, the components of the de-scaling composition aremixed together in a carrier comprising water or brine fluids.

In one embodiment, the composition may further comprise buffering agentsincluding organic and amino acids or their salts. Suitable buffersinclude citrate, gluconate, tartarate, malate, acetate, lactate,oxalate, aspartate, malonate, glucoheptonate, pyruvate, galactarate,glucarate, tartronate, glutamate, glycine, lysine, glutamine,methionine, cysteine, arginine and a mixture thereof. Phosphoric andphosphorous acids or their salts may also be used. Synthetic buffers aresuitable to be used but it is preferable to use natural buffers such asorganic and amino acids or their salts listed above.

In a further embodiment, pH adjusting agents include potassiumhydroxide, ammonium hydroxide, potassium carbonate or bicarbonate,hydrochloric acid, nitric acid, sulfuric acid or a mixture.

In one embodiment, additional components such as an aqueous preparationof a salt such as sodium bicarbonate or carbonate, sodium sulfate,sodium phosphate, sodium biphosphate, can be included in theformulation.

The compositions according to the subject invention can compriseingredients in amounts effective to enhance oil and/or gas recovery froma formation; as well as to perform the additional functions describedherein related to improving the quality of oil recovered from theformation, as well as maintenance of equipment associated with theformation.

In some embodiments, the multifunctional composition of the subjectinvention has advantageous electrostatic properties that provide forenhanced oil recovery. In general, each ingredient can have apH-dependent partial charge. The surfactants comprise non-ionic and/oranionic fractions. The non-ionic fractions are necessary for interactingwith the oil phase, as opposed to the water phase, of crude fluids.

Additionally, certain chelating agents can take on a negative charge.Along with the anionic surfactants, the chelating agents can serve asco-surfactants to help enhance penetration into the formation and intoscale deposits through the sequestering of positively charged ions(e.g., calcium ions) without the need for using strong acids. This alsohelps with inhibiting future deposition of scale.

Furthermore, the composition does not react with chlorine or organicchlorine complexes, and does not dissociate as easily as, for example,compounds used in acid scale removal, such as potassium hydroxide orhydrochloric acid, which are highly electrolytic.

Production of Microbial Growth By-Products

The subject invention provides methods for cultivation of microorganismsand production of microbial metabolites and/or other by-products ofmicrobial growth (e.g., biosurfactants, fatty acid esters). In oneembodiment, the subject invention provides materials and methods for theproduction of biomass (e.g., viable cellular material), extracellularmetabolites (e.g. small molecules and excreted proteins), residualnutrients and/or intracellular components (e.g. enzymes and otherproteins).

In one embodiment, the subject invention provides methods of producing amicrobial metabolite by cultivating a microbe strain of the subjectinvention under conditions appropriate for growth and production of themetabolite. In a specific embodiment, the metabolite is a surfactantaccording to the subject invention. The metabolite may also be, forexample, ethanol, lactic acid, beta-glucan, proteins, amino acids,peptides, metabolic intermediates, polyunsaturated fatty acids, andlipids. The metabolite content produced by the method can be, forexample, at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

In some embodiments, a microorganism produces more than one surfactantand/or other growth by-products at a time.

In certain embodiments, a microbe growth facility produces fresh,high-density microorganisms and/or microbial growth by-products ofinterest on a desired scale. The microbe growth facility may be locatedat or near the site of application, or at a different location. Thefacility produces high-density microbe-based compositions in batch,quasi-continuous, or continuous cultivation.

In certain embodiments, the microbe growth facilities of the subjectinvention can be located at or near the location where the microbe-basedproduct will be used (e.g., at or near an oil well). For example, themicrobe growth facility may be less than 300, 250, 200, 150, 100, 75,50, 25, 15, 10, 5, 3, or 1 mile from the location of use.

The microbe growth facilities can produce fresh, microbe-basedcompositions, comprising the microbes themselves, microbial metabolites,and/or other components of the medium in which the microbes are grown.If desired, the compositions can have a high density of vegetative cellsor a mixture of vegetative cells, spores, conidia, mycelia and/or othermicrobial propagules. Advantageously, the compositions can be tailoredfor use at a specified location.

If desired, the methods of the subject invention can harness the powerof naturally-occurring local microorganisms and their metabolicby-products to improve oil production, transmission and/or refining.Local microbes can be identified based on, for example, salt tolerance,ability to grow at high temperatures, and the use of geneticidentification of the sequences described herein.

The microbe growth facilities provide manufacturing versatility by theirability to tailor the microbe-based products to improve synergies withdestination geographies. The microbe growth facilities may operate offthe grid by utilizing, for example, solar, wind and/or hydroelectricpower. Thus, the microbe-based compositions can be produced in remotelocations. In some embodiments, however, the microbe growth facilitiesproduce the products at a different location, and package the product insuch a way as to allow for transporting the product to the oil well.

The growth vessel used for growing microorganisms can be any fermenteror cultivation reactor for industrial use. In one embodiment, the vesselmay have functional controls/sensors or may be connected to functionalcontrols/sensors to measure important factors in the cultivationprocess, such as pH, oxygen, pressure, temperature, agitator shaftpower, humidity, viscosity and/or microbial density and/or metaboliteconcentration.

In a further embodiment, the vessel may also be able to monitor thegrowth of microorganisms inside the vessel (e.g., measurement of cellnumber and growth phases). Alternatively, a daily sample may be takenfrom the vessel and subjected to enumeration by techniques known in theart, such as dilution plating technique. Dilution plating is a simpletechnique used to estimate the number of microbes in a sample. Thetechnique can also provide an index by which different environments ortreatments can be compared.

In one embodiment, the method comprises growing the microorganisms in anutrient medium. In one embodiment, the nutrient medium comprises anitrogen source. The nitrogen source can be, for example, potassiumnitrate, ammonium nitrate ammonium sulfate, ammonium phosphate, ammonia,urea, and/or ammonium chloride. These nitrogen sources may be usedindependently or in a combination of two or more.

The nutrient medium can further comprise a carbon source. The carbonsource is typically a carbohydrate, such as glucose, sucrose, lactose,fructose, trehalose, mannose, mannitol, and/or maltose; organic acidssuch as acetic acid, fumaric acid, citric acid, propionic acid, malicacid, malonic acid, and/or pyruvic acid; alcohols such as ethanol,isopropyl, propanol, butanol, pentanol, hexanol, isobutanol, and/orglycerol; fats and oils such as soybean oil, rice bran oil, canola oil,olive oil, corn oil, sesame oil, and/or linseed oil; etc. These carbonsources may be used independently or in a combination of two or more.

In one embodiment, the method comprises use of two carbon sources, oneof which is a saturated oil selected from canola, soy, sunflower,vegetable, corn, coconut, olive, or any other oil suitable for use in,for example, cooking.

In one embodiment, the microorganisms can be grown on a solid orsemi-solid substrate, such as, for example, corn, wheat, soybean,chickpeas, beans, oatmeal, pasta, rice, and/or flours or meals of any ofthese or other similar substances.

In one embodiment, growth factors and trace nutrients for microorganismsare included in the medium. This is particularly preferred when growingmicrobes that are incapable of producing all of the vitamins theyrequire. Inorganic nutrients, including trace elements such as iron,zinc, copper, manganese, molybdenum and/or cobalt may also be includedin the medium. Furthermore, sources of vitamins, essential amino acids,and microelements can be included, for example, in the form of flours ormeals, such as corn flour, or in the form of extracts, such as yeastextract, potato extract, beef extract, soybean extract, banana peelextract, and the like, or in purified forms.

In one embodiment, inorganic salts may also be included in the nutrientmedium. Usable inorganic salts can be potassium dihydrogen phosphate,dipotassium hydrogen phosphate, disodium hydrogen phosphate, magnesiumsulfate, magnesium chloride, iron sulfate, iron chloride, manganesesulfate, manganese chloride, zinc sulfate, lead chloride, coppersulfate, calcium chloride, calcium carbonate, sodium chloride and/orsodium carbonate. These inorganic salts may be used independently or ina combination of two or more.

In some embodiments, the method for cultivation may further compriseadding additional acids and/or antimicrobials in the liquid mediumbefore and/or during the cultivation process. Antimicrobial agents orantibiotics are used for protecting the culture against contamination.Additionally, antifoaming agents may also be added to prevent theformation and/or accumulation of foam during cultivation.

The method can provide oxygenation to the growing culture. Oneembodiment utilizes slow motion of air to remove low-oxygen containingair and introduce oxygenated air. In the case of submerged fermentation,the oxygenated air may be ambient air supplemented daily throughmechanisms including impellers for mechanical agitation of the liquid,and air spargers for supplying bubbles of gas to the liquid fordissolution of oxygen into the liquid.

The pH of the fermentation medium should be suitable for themicroorganism of interest. Buffers, and pH regulators, such ascarbonates and phosphates, may be used to stabilize pH near a preferredvalue. When metal ions are present in high concentrations, use of achelating agent in the liquid medium may be necessary.

In one embodiment, the method for cultivation of microorganisms iscarried out at about 5° to about 100° C., preferably, 15 to 60° C., morepreferably, 25 to 50° C. In a further embodiment, the cultivation may becarried out continuously at a constant temperature. In anotherembodiment, the cultivation may be subject to changing temperatures.

In one embodiment, the equipment used in the method and cultivationprocess is sterile. The cultivation equipment such as the reactor/vesselmay be separated from, but connected to, a sterilizing unit, e.g., anautoclave. The cultivation equipment may also have a sterilizing unit lthat sterilizes in situ before starting the inoculation. Air can besterilized by methods know in the art. For example, the ambient air canpass through at least one filter before being introduced into thevessel. In other embodiments, the medium may be pasteurized or,optionally, no heat at all added, where the use of low water activityand low pH may be exploited to control undesirable bacterial growth.

The biomass content of the fermentation medium may be, for example from5 g/l to 180 g/l or more, or from 10 g/l to 150 g/l or more.

The microbial growth by-product of interest may be retained in themicroorganisms or secreted into the growth medium. In anotherembodiment, the method for producing microbial growth by-product mayfurther comprise steps of concentrating and purifying the microbialgrowth by-product of interest. In a further embodiment, the medium maycontain compounds that stabilize the activity of microbial growthby-product.

The method for cultivation of microorganisms and production of themicrobial by-products can be performed in a batch, quasi-continuous, orcontinuous processes.

In one embodiment, all of the microbial cultivation composition isremoved upon the completion of the cultivation (e.g., upon, for example,achieving a desired cell density, or density of a specified metabolite).In this batch procedure, an entirely new batch is initiated uponharvesting of the first batch.

In another embodiment, only a portion of the fermentation product isremoved at any one time. In this embodiment, biomass with viable cellsremains in the vessel as an inoculant for a new cultivation batch. Thecomposition that is removed can be a microbe-free medium or containcells, spores, mycelia, conidia or other microbial propagules. In thismanner, a quasi-continuous system is created.

Advantageously, the methods of cultivation do not require complicatedequipment or high energy consumption. The microorganisms of interest canbe cultivated at small or large scale on site and utilized, even beingstill-mixed with their media. Similarly, the microbial metabolites canalso be produced, extracted and/or purified in large quantities at thesite of need.

Because, in certain embodiments, the microbe-based products can begenerated locally, without resort to the microorganism stabilization,preservation, storage and transportation processes of conventionalmicrobial production, a much higher density of live microbes, spores,mycelia, conidia or other microbial propagules can be generated, therebyrequiring a smaller volume of the microbe-based product for use in theon-site application or which allows much higher density microbialapplications where necessary to achieve the desired efficacy. Thisallows for a scaled-down bioreactor (e.g., smaller fermentation tank,smaller supplies of starter material, nutrients and pH control agents),which makes the system efficient. Local generation of the microbe-basedproduct also facilitates the inclusion of the growth medium in theproduct. The medium can contain agents produced during the fermentationthat are particularly well-suited for local use.

Advantageously, local microbe growth facilities provide a solution tothe current problem of relying on far-flung industrial-sized producerswhose product quality suffers due to upstream processing delays, supplychain bottlenecks, improper storage, and other contingencies thatinhibit the timely delivery and application of a viable product.

Local production and delivery within, for example, 24 hours offermentation results in stable compositions and substantially lowershipping costs. Given the prospects for rapid advancement in thedevelopment of more effective and powerful microbial products, consumerswill benefit greatly from this ability to rapidly deliver the products.

The microorganisms useful according to the subject invention can be, forexample, bacteria, yeast and/or fungi. These microorganisms may benatural, or genetically modified microorganisms. For example, themicroorganisms may be transformed with specific genes to exhibitspecific characteristics. The microorganisms may also be mutants of adesired strain. As used herein, “mutant” means a strain, genetic variantor subtype of a reference microorganism, wherein the mutant has one ormore genetic variations (e.g., a point mutation, missense mutation,nonsense mutation, deletion, duplication, frameshift mutation or repeatexpansion) as compared to the reference microorganism. Procedures formaking mutants are well known in the microbiological art. For example,UV mutagenesis and nitrosoguanidine are used extensively toward thisend.

In preferred embodiments, the microorganism is any yeast or fungus.Examples of yeast and fungus species suitable for use according to thecurrent invention, include, but are not limited to, Acaulospora,Aspergillus, Aureobasidium (e.g., A. pullulans), Blakeslea, Candida(e.g., C. albicans, C. apicola), Cryptococcus, Debaryomyces (e.g., D.hansenii), Entomophthora, Fusarium, Hanseniaspora (e.g., H. uvarum),Hansenula, Issatchenkia, Kluyveromyces, Mortierella, Mucor (e.g., M.piriformis), Meyerozyma (e.g., M. guilliermondii), Penicillium,Phythium, Phycomyces, Pichia (e.g., P. anomala, P. guielliermondii, P.occidentalis, P. kudriavzevii), Pseudozyma (e.g., P. aphidis), Rhizopus,Saccharomyces (S. cerevisiae, S. boulardii sequela, S. torula),Starmerella (e.g., S. bombicola), Torulopsis, Thraustochytrium,Trichoderma (e.g., T. reesei, T. harzianum, T. virens), Ustilago (e.g.,U. maydis), Wickerhamomyces (e.g., W. anomalus), Williopsis, andZygosaccharomyces (e.g., Z. bailii).

In certain embodiments, use of a yeast fermentation product according tothe subject invention can be superior to, for example, purifiedmicrobial metabolites alone, due to, for example, the advantageousproperties of the yeast cell walls. These properties include highconcentrations of mannoprotein as a part of yeast cell wall's outersurface (mannoprotein is a highly effective bioemulsifier) and thepresence of biopolymer beta-glucan (an emulsifier) in yeast cell walls.Additionally, the yeast fermentation product further can comprisesurfactants in the culture, which are capable of reducing both surfaceand interfacial tension, as well as other metabolites (e.g., lacticacid, ethyl acetate, ethanol, etc.) in the culture.

In some embodiments, the microorganisms are bacteria, includingGram-positive and Gram-negative bacteria. Bacteria suitable for useaccording to the present invention include, for example, Acinetobacter(e.g., A. calcoaceticus, A. venetianus); Agrobacterium (e.g., A.radiobacter), Azotobacter (A. vinelandii, A. chroococcum), Azospirillum(e.g., A. brasiliensis), Bacillus (e.g., B. amyloliquefaciens, B.firmus, B. laterosporus, B. licheniformis, B. megaterium, B.mucilaginosus, B. subtilis), Chlorobiaceae spp., Dyadobacter fermenters,Frankia spp., Frateuria (e.g., F. aurantia), Kiebsiella spp.,Microbacterium (e.g., M. laevaniformans), Pantoea (e.g., P.agglomerans), Pseudomonas (e.g., P. aeruginosa, P. chlororaphis, P.chlororaphis subsp. aureofaciens (Kluyver), P. putida), Rhizobium spp.,Rhodospirillum (e.g., R. rubrum), Sphingomonas (e.g., S. paucimobilis),and/or Xanthomonas spp.

Other microbial strains can be used in accordance with the subjectinvention, including, for example, any other microbial strains havinghigh concentrations of mannoprotein and/or beta-glucan in their cellwalls and/or that are capable of producing surfactants.

Preparation of Microbe-Based Products

In certain preferred embodiments, the compositions of the subjectinvention utilize biochemicals produced by microorganisms. These growthby-products can be used in a purified or crude form. In a specificembodiment, the growth by-products are surfactants.

One microbe-based product of the subject invention is simply thefermentation medium containing the microorganism and/or thebiosurfactants produced by the microorganism and/or any residualnutrients or other growth by-products. The product of fermentation maybe used directly without extraction or purification. If desired,extraction and purification can be easily achieved using standardextraction and/or purification methods or techniques described in theliterature.

The microorganisms in the microbe-based product may be in an active orinactive form. The microbe-based products may be used without furtherstabilization, preservation, and storage. Advantageously, direct usageof these microbe-based products reduces the possibility of contaminationfrom foreign agents and undesirable microorganisms, and maintains theactivity of the by-products of microbial growth.

The microbes and/or medium (e.g., broth or solid substrate) resultingfrom the microbial growth can be removed from the growth vessel andtransferred via, for example, piping for immediate use.

In one embodiment, the microbe-based product is simply the growthby-products of the microorganism. For example, biosurfactants producedby a microorganism can be collected from a submerged fermentation vesselin crude form, comprising, for example about 0.001% to about 99% purebiosurfactant in liquid broth. The biosurfactant can be furtherpurified, if desired.

In other embodiments, the microbe-based product (microbes, medium, ormicrobes and medium) can be placed in containers of appropriate size,taking into consideration, for example, the intended use, thecontemplated method of application, the size of the fermentation vessel,and any mode of transportation from microbe growth facility to thelocation of use. Thus, the containers into which the microbe-basedcomposition is placed may be, for example, from 1 gallon to 1,000gallons or more. In other embodiments the containers are 2 gallons, 5gallons, 25 gallons, or larger.

Upon harvesting, further components can be added to the microbe-basedproduct as the harvested product is placed into containers and/or piped(or otherwise transported for use). The additives can be, for example,buffers, carriers, other microbe-based compositions produced at the sameor different facility, viscosity modifiers, lubricants, surfactants,emulsifying agents, preservatives, nutrients for microbe growth,tracking agents, solvents, biocides, solubility controlling agents, pHadjusting agents, stabilizers, ultra-violet light resistant agents,and/or other microbes and other ingredients specific for an intendeduse.

In one embodiment, buffering agents can be included, such as, forexample, organic and amino acids or their salts. Suitable buffersinclude citrate, gluconate, tartarate, malate, acetate, lactate,oxalate, aspartate, malonate, glucoheptonate, pyruvate, galactarate,glucarate, tartronate, glutamate, glycine, lysine, glutamine,methionine, cysteine, arginine and a mixture thereof. Phosphoric andphosphorous acids or their salts may also be used. Synthetic buffers aresuitable to be used but it is preferable to use natural buffers such asorganic and amino acids or their salts listed above.

In a further embodiment, pH adjusting agents include potassiumhydroxide, ammonium hydroxide, potassium carbonate or bicarbonate,hydrochloric acid, nitric acid, sulfuric acid or a mixture.

In one embodiment, additional components such as an aqueous preparationof a salt, such as sodium bicarbonate or carbonate, sodium sulfate,sodium phosphate, sodium biphosphate, can be included in theformulation.

Optionally, the product can be stored prior to use. The storage time ispreferably short. Thus, the storage time may be less than 60 days, 45days, 30 days, 20 days, 15 days, 10 days, 7 days, 5 days, 3 days, 2days, 1 day, or 12 hours. In a preferred embodiment, if live cells arepresent in the product, the product is stored at a cool temperature suchas, for example, less than 20° C., 15° C., 10° C., or 5° C. On the otherhand, a biosurfactant composition can typically be stored at ambienttemperatures.

Advantageously, in accordance with the subject invention, themicrobe-based product may comprise medium in which the microbes weregrown. The product may be, for example, at least, by weight, 1%, 5%,10%, 25%, 50%, 75%, or 100% growth medium. The amount of biomass in theproduct, by weight, may be, for example, anywhere from 0% to 100%inclusive of all percentages therebetween.

Methods of Enhancing Oil Recovery

The subject invention provides efficient methods for improving oilproduction, wherein one or more concentrated acids one or moresurfactants, one or more chelating agents, and one or more solvents areapplied into an oil-bearing formation, an oil well and/or a wellbore.Optionally, one or more co-surfactants are also applied. In specificembodiments, the methods provide for enhanced acid washing and/oracidizing treatments,

In one embodiment, the methods comprise applying a multipurpose EORcomposition of the subject invention to the formation, oil well and/orwellbore. Advantageously, the subject invention can utilize onetreatment to perform a variety of functions, in addition to EOR,including improving the quality of crude fluids, and maintenance of oilproduction and processing equipment. In some embodiments, thesefunctions are interrelated. This invention is particularly useful invertical wells, but can also be used to enhance oil recovery inhorizontal wells as well as from wells that have experienced a declinein oil production rates, including depleted stripper (marginal) wells.

As used herein, “applying” a composition or product refers to contactingit with a target or site such that the composition or product can havean effect on that target or site. The effect can be due to, for example,the action of an acid, surfactant, chelator, solvent and/or asynergistic combination thereof. For example, the compositions can beinjected into oil wells and/or the piping, tubulars, wellbore, casing,annulus, pumps, and tanks associated with oil-bearing formations, oilwells, oil production, oil transmission and oil transportation.

In an exemplary embodiment, the methods comprise pumping, for example,100 to 1,000 gallons per foot of formation of the composition into andout of an oil well. Injection rates can be determined by a skilled oilwell operation, although, as an example, an injection rate of 1 to 20gallons per minute, or 1 to 20 barrels per minute can be used in someembodiments. In preferred embodiments, no shut-in time is required.

Application of the multipurpose EOR composition can be performed duringdrilling operations (e.g., while drilling, while tripping-in ortripping-out of the hole, while circulating mud, while casing, whileplacing a production liner, and/or while cementing, etc.). Applicationcan also occur as a production treatment, for example, by introducingthe composition into an oil well after oil production is underway and/orafter a decline in the rate of oil production from the formation hasoccurred.

In some embodiments, the composition can be introduced into theformation through perforations in the casing. The composition may beforced into the surrounding formation by applied pressure or, if thecomposition is allowed to set at the bottom of the casing, thecomposition may seep into the formation without additional pressure. Thecomposition permeates the formation, improving the rate of oil recoveryby a number of mechanisms such as, for example, dissolving contaminantblockages in the formation pore throats.

The composition may be introduced by means of injection pumps intooff-shore gas or oil wells to reduce contaminants in well casings andtransmission lines. In addition to the problems associated with land oilwells, the lines and contents between the bottom of the ocean and theplatform associated with off-shore wells are cooled by the ocean or seawater, thus increasing the crystallization and deposition rate of scale,paraffin and asphaltene. To treat the lines, from 1-500 gallons up to1000 barrels, 10,000 barrels, or more, for example, of the compositioncan be introduced therein.

The subject treatment can be effective in a range of different geologicformations. For example, the subject invention can be useful informations as deep as about 7,000 feet or deeper, and as shallow asabout 1,500 feet or shallower. Additionally, the invention can be usefulin formations having a range of porosity and/or permeability, forexample from about 0.1% to about 20% or more. The invention can also beuseful in formations having a wide range of temperatures, pH, andsalinity.

In some embodiments, the methods result in EOR through, for example,stimulation of the flow of oil from an oil well; prevention and/orreduction of asphaltene agglomeration in oil and/or deposition onequipment surfaces; dispersal of paraffin deposits; increase in themobility of crude oil during recovery; and increase in the wettabilityof formation rock.

Furthermore, in some embodiments, the concentrated acid works in synergywith the one or more surfactants, one or more chelating agents, one ormore solvents, and/or one or more optional co-surfactants, to dissolveand/or disperse mineral scale deposits that have deposited in, forexample, tubulars, in the wellbore, and/or that have plugged rock porethroats in a formation. In certain embodiments, this synergy providesfor enhanced acid treatments, meaning the treatment is more effectivefor stimulating the flow of oil from a formation than using concentratedacids alone.

Advantageously, the subject methods can free clogged reservoir pores,channels and/or tubing, and/or reduce the capillary pressure—a majorfactor controlling the fluid distribution in a reservoir rock. Capillarypressure is observable in the presence of two immiscible fluids incontact with each other in capillary-like tubes. The small pores in areservoir rock are similar to capillary tubes and they usually containtwo immiscible fluid phases in contact with each other. Unblockingclogged pores and decreasing the capillary pressure allows for increasedoil production from depleted wells, and further, even allowinginoperable wells to resume normal operation.

In one embodiment, the methods can also be used for improving thequality of crude oil recovered from a formation. Improved crude oilquality can be achieved through, for example, the sequestration and/orremoval of heavy metals, such as nickel and/or vanadium, present in theoil; reduction and/or prevention of asphaltene agglomerates in the oil;and modulation (increase or decrease) in the acidity of the oil andother formation fluids.

In certain embodiments, the methods can also be used for maintenance ofequipment, for example, pipes, tubulars, drills, pumps, casings, tanks,rods, boreholes, and other structures and equipment involved in oiland/or gas production and processing. In some embodiments, thecomposition may be applied directly to equipment. For example, prior toplacing rods and casings into gas and/or oil wells, these parts may besprayed with, or soaked in, the composition. The parts may be dippedinto tanks filled with the composition to prevent under-depositcorrosion and buildup of contaminants.

Any equipment or component of oil production, processing,transportation, storage and/or refining can be treated and maintainedwith a composition of the subject invention. Advantageously, the subjectinvention can be applied to equipment involved in all stages of thechain of operations, including exploration and production (E&P) (e.g.,onshore and offshore wellbores, flowlines, and tanks), midstream (e.g.,pipelines, tankers, transportation, storage tanks), and in refineries(e.g., heat exchangers, furnaces, distillation towers, cokers,hydrocrackers).

In one embodiment, maintenance of equipment is achieved through theprevention, removal, and/or dispersal of contaminating deposits thatform on the equipment. There are many types of contaminants associatedwith oil production equipment, such as scales, oils, paraffins,asphalts/asphaltenes, resins, sulfur, tar by-products, biofilms, andother viscous materials. The composition of the present invention can beused to remove any one or more of the contaminants associated with oilrecovery, transmission and processing. In certain specific embodiments,the contaminant is scale.

In one embodiment, the subject invention can be used for preventingprecipitation and/or deposition of contaminants from occurring. Thus,the present invention allows for delaying or completely removing thenecessity for preventative maintenance related to removing precipitatesand deposits, as well as the need for replacing or repairing equipmentparts.

In one embodiment, a method of cleaning and maintaining a working well,including the surrounding formation, includes the steps of pouring orinjecting the composition down the casing side (back lines) of a welland allowing it to mix with the fluid that is already in the well. Whenenough fluid is present, the composition can then optionally becirculated by, for example, a pump for 24-72 hours, preferably 48-72hours. Prior to circulating, the composition may be allowed to set for 8to 24 hours, for example. The setting time, circulating time and dosagedepend on the amount of scale and/or other contaminant anticipated to bepresent, as well as the depth and size of the well. A basic initialdosage can be, but is not limited to, 20 gallons of composition and formaintaining a clear structure, at least about 5 gallons of compositionper well on periodic basis, e.g., biweekly, monthly, bimonthly.

The subject composition can further be applied for dissolving anddispersal of contaminant buildup in, for example, storage andtransportation tanks, tankers, ships, trucks, pipelines and flowlines,without need for mechanical cleaning solutions or toxic solvents.Methods of cleaning tanks are provided, which can be effective fordispersing contaminant buildup in a matter of days, for example, lessthan a week.

In one embodiment, methods of cleaning a storage or transportation tankare provided, wherein air or methane is injected under pressure into atank. This can either be preceded by or followed by injection of thesubject de-scaling composition. Waste water is pumped to a treatmentplant after treatment with the subject composition. Preferably, the airor methane is injected into the tank to allow for approximately 10minutes of roiling.

Advantageously, in some embodiments, the subject treatments can freeclogged pores, channels and/or tubing, allowing for increased oilproduction from depleted wells, and further, even allowing inoperablewells to resume normal operation. Additionally, through a variety ofmechanisms, the subject treatments can stimulate wells, improve thequality of crude oil, and help in the maintenance of oil production andprocessing equipment.

We claim:
 1. A composition for enhancing oil recovery from anoil-bearing formation, the composition comprising an acid, abiosurfactant, a chelating agent, and a solvent.
 2. The composition ofclaim 1, comprising an acid selected from hydrochloric acid,hydrofluoric acid, and organic acids.
 3. The composition of claim 1,comprising a biosurfactant selected from glycolipids, cellobiose lipids,lipopeptides, fatty acid ester compounds, flavolipids, phospholipids,high-molecular-weight biopolymers, lipoproteins,lipopolysaccharide-protein complexes, and polysaccharide-protein-fattyacid complexes.
 4. The composition of claim 3, comprising asophorolipid.
 5. The composition of claim 1, comprising a chelatingagent selected from dimercaptosuccinic acid (DMSA),2,3-dimercaptopropanesulfonic acid (DMPS), alpha lipoic acid (ALA),thiamine tetrahydrofurfuryl disulfide (TTFD), penicillamine,ethylenediaminetetraacetic acid (EDTA), sodium acetate, sodium citrateand citric acid.
 6. The composition of claim 5, wherein the chelatingagents comprise a mixture of EDTA, sodium citrate and citric acid. 7.The composition of claim 1, comprising a solvent selected from alcohols,and ionic and/or semi-ionic liquids.
 8. The composition of claim 7,comprising an alcohol selected from ethanol, butanol, propanol, andisopropyl alcohol.
 9. A composition for enhancing oil recovery from anoil well, the composition comprising water, hydrochloric acid, abiosurfactant, isopropyl alcohol, and a mixture of EDTA, sodium citrateand citric acid.
 10. The composition of claim 9, comprising abiosurfactant selected from mannosylerythritol lipids and sophorolipids.11. A method for enhancing oil recovery from an oil-bearing formation,the method comprising introducing a composition of claim 1 into theformation, and/or into an oil well and/or wellbore associated with theformation.
 12. The method of claim 11, wherein the flow of oil from thesubterranean formation is stimulated.
 13. The method of claim 11,wherein scale and/or paraffin deposits that have plugged rock porethroats in the formation are dissolved and/or dispersed.
 14. The methodof claim 11, wherein asphaltene agglomeration in oil is prevented and/orreduced, and/or deposition of asphaltene on surfaces of equipmentassociated with the formation is prevented and/or reduced.
 15. Themethod of claim 11, wherein the mobility of oil is increased duringrecovery.
 16. The method of claim 11, wherein the wettability of theformation rock is increased.
 17. The method of claim 11, wherein, inaddition to enhancing oil recovery, the method improves the quality ofrecovered oil.
 18. The method of claim 17, wherein oil quality isimproved by reduction and/or prevention of asphaltene agglomerates inthe oil.
 19. The method of claim 11, comprising introducing water and acomposition comprising 1% to 20% v/v hydrochloric acid, 5 to 10 ml/Lglycolipid surfactant, 2 to 4 ml/L isopropyl alcohol, and a mixturecomprising 5 to 10 g/L sodium citrate, 5 to 10 g/L citric acid, and 5 to10 g/L EDTA, into the formation, oil well and/or wellbore.